TROJ_CRYPWALL.YB
Trojan:Win32/Anaki.A (Microsoft); PWSZbot-FAEC!135C144CABB3 (McAfee); Trojan-Ransom.Win32.Cryptodef.bsk (Kaspersky); Troj/Ransom-ALZ (Sophos); Trojan.Win32.Generic!BT (Sunbelt); Trojan horse Inject2.AXKK (AVG)
Windows
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It deletes itself after execution.
TECHNICAL DETAILS
Arrival Details
This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
Installation
This Trojan drops the following files:
- %Desktop%\DECRYPT_INSTRUCTION.HTML
- %Desktop%\DECRYPT_INSTRUCTION.TXT
- %Desktop%\DECRYPT_INSTRUCTION.URL
(Note: %Desktop% is the desktop folder, where it usually is C:\Documents and Settings\{user name}\Desktop in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\Desktop in Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\(UID)\
{Random Key}
{path and file name of encrypted file} = "{Hex Values}"
HKEY_CURRENT_USER\Software\(UID)
{Random Entry} = "{Hex Values}"
HKEY_CURRENT_USER\Software\(UID)
{Random Entry} = "[DEFAULT]BASEURL=https://kpai7ycr7jxqkilp.torminater.com/{Random Letter 1}[InternetShortcut]URL=https://kpai7ycr7jxqkilp.torminater.com/{Random Letter 1}"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
{Random Key} = "%System Root%\{random folder name}\{random folder name}.exe"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
{random folder name} = "%Application Data%\{random folder name}.exe
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random key} = "%System Root%\{random folder name}\{random folder name}.exe"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random folder name} = "%Application Data%\{random folder name}.exe"
It drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:
- %User Startup%\{random folder name}.exe
(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.)
Other System Modifications
This Trojan adds the following registry keys:
HKEY_CURRENT_USER\Software\(UID)
HKEY_CURRENT_USER\Software\(UID)\
{Random Key}
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SystemRestore
DisableSR = "1"
(Note: The default value data of the said registry entry is "0".)
Other Details
This Trojan connects to the following possibly malicious URL:
- http://{BLOCKED}ntin.com
- http://{BLOCKED}poster.com
- http://{BLOCKED}tsp.com
- http://{BLOCKED}y.com
- http://{BLOCKED}nih.com
It deletes itself after execution.